Nowadays sugar alternatives are receiving increasing attention due to awareness of many diseases in conjunction with consumption of high-sugar foods and beverages. However many artificial sweeteners such as dulcin, sodium cyclamate and saccharin were banned or restricted in some countries due to concerns on their safety. Therefore non-caloric sweeteners of natural origin are becoming increasingly popular. The sweet herb Stevia rebaudiana Bertoni produces a number of diterpene glycosides which feature high intensity sweetness and sensory properties superior to that of many other high potency sweeteners.
The above-mentioned sweet glycosides have a common aglycon, steviol, and differ by the number and type of carbohydrate residues at the C13 and C19 positions. The leaves of Stevia are able to accumulate up to 10-20% (on dry weight basis) steviol glycosides. The major glycosides found in Stevia leaves are rebaudioside A (2-10%), stevioside (2-10%), and rebaudioside C (1-2%). Other glycosides such as rebaudioside B, D, E, and F, steviolbioside and rubusoside are found at much lower levels (approx. 0-0.2%).
Methods for the extraction and purification of sweet glycosides from the Stevia rebaudiana plant using water or organic solvents are described in, for example, U.S. Pat. Nos. 4,361,697; 4,082,858; 4,892,938; 5,972,120; 5,962,678; 7,838,044 and 7,862,845.
As it is well known the use of high intensity sweeteners in various applications requires various bulking agents to substitute the sugar which is removed from the formulation. The bulking agents used in those applications include both caloric and non-caloric materials. Non limiting examples of bulking agents include fructooligosaccharides, inulin, inulooligosaccharides, maltooligosaccharides, maltodextins, cyclodextrins, corn syrup solids, erythritol and other sugar alcohols, glucose, maltose, lactose, tagatose, lactulose, palatinose, isomalt, modified starches etc.
Obviously more preferable are the bulking agents which provide zero calories, such as erythritol, isomalt, fructooloigosacharides, inulin etc.
On the other hand it has to be noted that steviol glycosides are compounds extracted from the plant and in process of their manufacture large amounts of “empty” biomass is created. Moreover, generally, the extraction process utilizes only the Stevia plant leaves. This additionally generates large amount of the stems which have limited use as well. The “empty” biomass is mainly discharged directly to environment. In some cases it is used for biogas production. It might be used as biofertilizer as well. The stems are generally used as fuel.
There is no reports to-date on processing the stevia biomass into any food ingredient. Nevertheless, if accomplished in large scale, this can provide significant economic, and environmental benefits as it can provide an opportunity for inclusion of whole stevia plant into food chain, creating practically wasteless stevia processing.
Within the description of this invention we will show that, stevia plant biomass may be used as a source for producing valuable food ingredients and other chemicals, which can be used in number of areas including food and beverage applications.